Skip to main content


Press Releases

City and County to Spray for Mosquitoes in Four Square Miles of South Fort Collins

Released on Wednesday, September 5, 2018
Contact Information
  • City of Fort Collins Image
    The City will spray for West Nile-infected mosquitos in southeast Fort Collins this week

Based on high levels of infected Culex mosquitoes trapped in recent weeks, the City of Fort Collins and the Larimer County Health Department hope to decrease the risk of human West Nile virus infection by spraying for mosquitoes in a four-square-mile section of South Fort Collins. Please see the attached map for the specific area or visit to view the map.

The adult mosquito control will occur by fogging trucks on Thursday, September 6 and again in the same location Sunday, September 9, weather permitting. Spraying will begin at dusk and end by 2 a.m. each night. In alignment with the City’s Integrated Pest Management policy, only four square miles in the southeast zone of the City will be sprayed. The Vector index in the spray area is 1.28, which exceeds the City’s threshold to spray of 0.75.

The City’s contractor, Vector Disease Control International, will use a permethrin-based product to be applied in a fine mist. To minimize pesticide exposure, residents should stay indoors and keep doors and windows closed for 30 to 60 minutes after spraying. It’s recommended that residents bring pets indoors as well. Residents can further minimize pesticide exposure by covering organic gardens, ponds and water features with a cloth sheet, or tarp. West Nile Virus can be prevented. In addition to community control efforts, such as larviciding, reducing water where mosquitoes can breed, and spraying for adult mosquitoes, individuals should remember to use the 4 D’s to help prevent West Nile virus disease:

  • Defend (with mosquito repellent) - Use a mosquito repellent that has been proven to be effective against West Nile Virus-carrying mosquitoes. DEET, Picaridin, Oil of Lemon Eucalyptus (also called p-menthane-3,8-diol or PMD) and IR3535 are recommended.
  • Dusk to Dawn - Avoid exposure during peak Culex mosquito feeding times, from dusk through dawn.
  • Dress - Wear long sleeves and pants to keep mosquitoes from biting.
  • Drain – Remove standing water in your yard or garden to minimize mosquito breeding areas.

For more tips on what you can do to prevent West Nile virus, visit or